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Graft transmission of induced and spontaneous post‐transcriptional silencing of chitinase genes
Author(s) -
Crété Patrice,
Leuenberger Sabrina,
Iglesias Victor A.,
Suarez Vivian,
Schöb Hanspeter,
Holtorf Hauke,
Van Eeden Sjoerd,
Meins Frederick
Publication year - 2001
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1046/j.1365-313x.2001.01171.x
Subject(s) - gene silencing , sense (electronics) , transgene , biology , gene , transcription (linguistics) , microbiology and biotechnology , genetics , chemistry , philosophy , linguistics
Summary Sense and antisense tobacco chitinase ( CHN ) transgenes, Luciferase‐CHN transcriptional fusions, and promoterless CHN cDNAs were introduced biolistically into CHN transformants of tobacco that never exhibit spontaneous gene silencing. All of the constructs tested induced systemic silencing of the resident CHN transgene and endogenes. Nuclear run‐on transcription assays showed that local introduction of additional gene copies triggers systemic post‐transcriptional gene silencing (PTGS). Together, this provides evidence that additional transgene copies need not be either highly transcribed or produce sense transcripts to evoke production of systemic PTGS signals. CHN PTGS was transmitted by top grafting, but not by reciprocal grafting of mature stems or the exchange of tissue plugs. Thus, the commonly encountered difficulties in achieving graft‐transmission could reflect the method used. Silencing in sense but not antisense transformants was transmitted by grafting to a high‐expressing sense CHN scion suggesting that the elaboration of mobile signals may not be an essential feature of antisense‐mediated gene silencing.